import type { ChatMessage, PromptPreprocessorController } from "@lmstudio/sdk";
import { parseActivation } from "./activation";
import { splitFrontmatter, type Catalog } from "./catalog";
import { configSchematics, expandHome, globalConfigSchematics } from "./config";
import {
  hasSkillMarker,
  renderActiveReference,
  renderError,
  renderHint,
  renderMessage,
  renderNote,
  renderReadError,
  renderSkillBlock,
} from "./render";
import { jevJudge, resolveApiKey } from "./judge";
import { pickSkills, type SkillPick } from "./router";
import { HISTORY_TEXT_CAP, type Judge, type Settings, type Skill, type SkillFs, type Turn } from "./types";

export interface PreprocessDeps {
  catalog: Catalog;
  fs: SkillFs;
  /** Injected for tests. Production builds a jev judge that reads the plugin's jevApiKey setting. */
  judge?: Judge;
}

function readSettings(ctl: PromptPreprocessorController): Settings {
  const c = ctl.getPluginConfig(configSchematics);
  return {
    threshold: c.get("threshold"),
    maxSkills: c.get("maxSkills"),
    historyTurns: c.get("historyTurns"),
    maxInjectedChars: c.get("maxInjectedChars"),
    showHintWhenNoMatch: c.get("showHintWhenNoMatch"),
  };
}

async function readBody(fs: SkillFs, skill: Skill): Promise<string> {
  const text = (await fs.readFile(skill.skillMdPath)).toString("utf8");
  return splitFrontmatter(text).body;
}

/** The user hit stop. Only the controller's signal means "cancelled"; a jev deadline surfaces as a normal error. */
function isAbort(signal: AbortSignal): boolean {
  return signal.aborted;
}

export function createPreprocess(deps: PreprocessDeps) {
  // Production judge re-reads the key from the latest ctl on every call; tests inject a fixed Judge.
  let liveCtl: PromptPreprocessorController | undefined;
  const productionJudge =
    deps.judge ??
    jevJudge(() => resolveApiKey(liveCtl!.getPluginConfig(configSchematics).get("jevApiKey")));

  return async function preprocess(ctl: PromptPreprocessorController, userMessage: ChatMessage): Promise<string | ChatMessage> {
    liveCtl = ctl;
    try {
      return await run(ctl, userMessage, deps.judge ?? productionJudge);
    } catch (e) {
      const reason = e instanceof Error ? e.message : String(e);
      ctl.debug("skills: preprocessor failed, passing message through", reason, e);
      return userMessage;
    }
  };

  async function run(ctl: PromptPreprocessorController, userMessage: ChatMessage, judge: Judge): Promise<string | ChatMessage> {
    const text = userMessage.getText();
    const root = expandHome(ctl.getGlobalPluginConfig(globalConfigSchematics).get("skillsRoot"));
    const index = await deps.catalog.load(root);
    if (index.skills.length === 0) return userMessage;
    const settings = readSettings(ctl);

    const described = index.skills.filter(s => s.description !== "");

    // 1. Explicit activation.
    const act = parseActivation(text);
    if (act) {
      const skill = index.byName.get(act.name);
      if (!skill) return `${text}\n\n${renderError(act.name, [...index.byName.values()])}`;
      let body: string;
      try {
        body = await readBody(deps.fs, skill);
      } catch (e) {
        const reason = e instanceof Error ? e.message : String(e);
        ctl.debug("skills: could not read SKILL.md for explicit activation", reason, e);
        return `${text}\n\n${renderReadError(skill.name, reason)}`;
      }
      const block = renderSkillBlock(skill, body, { source: "explicit", maxInjectedChars: settings.maxInjectedChars });
      cite(ctl, skill);
      return renderMessage([block, renderNote()], act.rest);
    }

    // 2. Auto-routing.
    if (settings.maxSkills === 0 || index.routable.length === 0) {
      return settings.showHintWhenNoMatch ? renderMessage([renderHint(described)], text) : userMessage;
    }

    const history = (await ctl.pullHistory()).getMessagesArray();
    const status = ctl.createStatus({ status: "loading", text: "Routing skills…" });

    let picks: SkillPick[];
    try {
      const recentTurns = recent(history, settings.historyTurns);
      const probabilities = await judge({ message: text, recentTurns }, index.routable, ctl.abortSignal);
      picks = pickSkills(probabilities, settings);
    } catch (e) {
      if (isAbort(ctl.abortSignal)) {
        status.setState({ status: "canceled", text: "Skill routing canceled" });
        return userMessage;
      }
      const reason = e instanceof Error ? e.message : String(e);
      ctl.debug("skills: jev routing failed", reason, e);
      status.setState({ status: "done", text: `Skills: jev unavailable (${reason}); listed available skills instead` });
      return renderMessage([renderHint(described)], text);
    }

    if (picks.length === 0) {
      status.setState({ status: "done", text: "No skill applied" });
      return settings.showHintWhenNoMatch ? renderMessage([renderHint(described)], text) : userMessage;
    }

    // 3. Render picks, deduplicating against earlier turns.
    const blocks: string[] = [];
    try {
      const priorUserText = history.filter(m => m.getRole() === "user").map(m => m.getText());
      for (const pick of picks) {
        const skill = index.byName.get(pick.name);
        if (!skill) continue;
        if (priorUserText.some(t => hasSkillMarker(t, skill.name))) {
          blocks.push(renderActiveReference(skill));
        } else {
          blocks.push(renderSkillBlock(skill, await readBody(deps.fs, skill), { source: "jev", p: pick.p, maxInjectedChars: settings.maxInjectedChars }));
          cite(ctl, skill);
        }
      }
      blocks.push(renderNote());
    } catch (e) {
      const reason = e instanceof Error ? e.message : String(e);
      status.setState({ status: "error", text: `Skills: could not read a skill file (${reason})` });
      throw e;
    }
    status.setState({ status: "done", text: `Applied skills: ${picks.map(p => p.name).join(", ")}` });
    return renderMessage(blocks, text);
  }
}

function recent(history: ChatMessage[], turns: number): Turn[] {
  if (turns <= 0) return [];
  return history.slice(-turns).map(m => ({ role: m.getRole(), text: m.getText().slice(0, HISTORY_TEXT_CAP) }));
}

function cite(ctl: PromptPreprocessorController, skill: Skill) {
  ctl.createCitationBlock(skill.description || skill.name, { fileName: `${skill.name}/SKILL.md`, fileIdentifier: skill.skillMdPath });
}

import type { ChatMessage, PromptPreprocessorController } from "@lmstudio/sdk";
import { parseActivation } from "./activation";
import { splitFrontmatter, type Catalog } from "./catalog";
import { configSchematics, expandHome, globalConfigSchematics } from "./config";
import {
  hasSkillMarker,
  renderActiveReference,
  renderError,
  renderHint,
  renderMessage,
  renderNote,
  renderReadError,
  renderSkillBlock,
} from "./render";
import { jevJudge, resolveApiKey } from "./judge";
import { pickSkills, type SkillPick } from "./router";
import { HISTORY_TEXT_CAP, type Judge, type Settings, type Skill, type SkillFs, type Turn } from "./types";

export interface PreprocessDeps {
  catalog: Catalog;
  fs: SkillFs;
  /** Injected for tests. Production builds a jev judge that reads the plugin's jevApiKey setting. */
  judge?: Judge;
}

function readSettings(ctl: PromptPreprocessorController): Settings {
  const c = ctl.getPluginConfig(configSchematics);
  return {
    threshold: c.get("threshold"),
    maxSkills: c.get("maxSkills"),
    historyTurns: c.get("historyTurns"),
    maxInjectedChars: c.get("maxInjectedChars"),
    showHintWhenNoMatch: c.get("showHintWhenNoMatch"),
  };
}

async function readBody(fs: SkillFs, skill: Skill): Promise<string> {
  const text = (await fs.readFile(skill.skillMdPath)).toString("utf8");
  return splitFrontmatter(text).body;
}

/** The user hit stop. Only the controller's signal means "cancelled"; a jev deadline surfaces as a normal error. */
function isAbort(signal: AbortSignal): boolean {
  return signal.aborted;
}

export function createPreprocess(deps: PreprocessDeps) {
  // Production judge re-reads the key from the latest ctl on every call; tests inject a fixed Judge.
  let liveCtl: PromptPreprocessorController | undefined;
  const productionJudge =
    deps.judge ??
    jevJudge(() => resolveApiKey(liveCtl!.getPluginConfig(configSchematics).get("jevApiKey")));

  return async function preprocess(ctl: PromptPreprocessorController, userMessage: ChatMessage): Promise<string | ChatMessage> {
    liveCtl = ctl;
    try {
      return await run(ctl, userMessage, deps.judge ?? productionJudge);
    } catch (e) {
      const reason = e instanceof Error ? e.message : String(e);
      ctl.debug("skills: preprocessor failed, passing message through", reason, e);
      return userMessage;
    }
  };

  async function run(ctl: PromptPreprocessorController, userMessage: ChatMessage, judge: Judge): Promise<string | ChatMessage> {
    const text = userMessage.getText();
    const root = expandHome(ctl.getGlobalPluginConfig(globalConfigSchematics).get("skillsRoot"));
    const index = await deps.catalog.load(root);
    if (index.skills.length === 0) return userMessage;
    const settings = readSettings(ctl);

    const described = index.skills.filter(s => s.description !== "");

    // 1. Explicit activation.
    const act = parseActivation(text);
    if (act) {
      const skill = index.byName.get(act.name);
      if (!skill) return `${text}\n\n${renderError(act.name, [...index.byName.values()])}`;
      let body: string;
      try {
        body = await readBody(deps.fs, skill);
      } catch (e) {
        const reason = e instanceof Error ? e.message : String(e);
        ctl.debug("skills: could not read SKILL.md for explicit activation", reason, e);
        return `${text}\n\n${renderReadError(skill.name, reason)}`;
      }
      const block = renderSkillBlock(skill, body, { source: "explicit", maxInjectedChars: settings.maxInjectedChars });
      cite(ctl, skill);
      return renderMessage([block, renderNote()], act.rest);
    }

    // 2. Auto-routing.
    if (settings.maxSkills === 0 || index.routable.length === 0) {
      return settings.showHintWhenNoMatch ? renderMessage([renderHint(described)], text) : userMessage;
    }

    const history = (await ctl.pullHistory()).getMessagesArray();
    const status = ctl.createStatus({ status: "loading", text: "Routing skills…" });

    let picks: SkillPick[];
    try {
      const recentTurns = recent(history, settings.historyTurns);
      const probabilities = await judge({ message: text, recentTurns }, index.routable, ctl.abortSignal);
      picks = pickSkills(probabilities, settings);
    } catch (e) {
      if (isAbort(ctl.abortSignal)) {
        status.setState({ status: "canceled", text: "Skill routing canceled" });
        return userMessage;
      }
      const reason = e instanceof Error ? e.message : String(e);
      ctl.debug("skills: jev routing failed", reason, e);
      status.setState({ status: "done", text: `Skills: jev unavailable (${reason}); listed available skills instead` });
      return renderMessage([renderHint(described)], text);
    }

    if (picks.length === 0) {
      status.setState({ status: "done", text: "No skill applied" });
      return settings.showHintWhenNoMatch ? renderMessage([renderHint(described)], text) : userMessage;
    }

    // 3. Render picks, deduplicating against earlier turns.
    const blocks: string[] = [];
    try {
      const priorUserText = history.filter(m => m.getRole() === "user").map(m => m.getText());
      for (const pick of picks) {
        const skill = index.byName.get(pick.name);
        if (!skill) continue;
        if (priorUserText.some(t => hasSkillMarker(t, skill.name))) {
          blocks.push(renderActiveReference(skill));
        } else {
          blocks.push(renderSkillBlock(skill, await readBody(deps.fs, skill), { source: "jev", p: pick.p, maxInjectedChars: settings.maxInjectedChars }));
          cite(ctl, skill);
        }
      }
      blocks.push(renderNote());
    } catch (e) {
      const reason = e instanceof Error ? e.message : String(e);
      status.setState({ status: "error", text: `Skills: could not read a skill file (${reason})` });
      throw e;
    }
    status.setState({ status: "done", text: `Applied skills: ${picks.map(p => p.name).join(", ")}` });
    return renderMessage(blocks, text);
  }
}

function recent(history: ChatMessage[], turns: number): Turn[] {
  if (turns <= 0) return [];
  return history.slice(-turns).map(m => ({ role: m.getRole(), text: m.getText().slice(0, HISTORY_TEXT_CAP) }));
}

function cite(ctl: PromptPreprocessorController, skill: Skill) {
  ctl.createCitationBlock(skill.description || skill.name, { fileName: `${skill.name}/SKILL.md`, fileIdentifier: skill.skillMdPath });
}