// internal/skills/spec/handlers.go
package spec

import (
	"context"
	"encoding/json"
	"fmt"
	"time"

	"github.com/mathiasbq/supervisor/internal/brain"
	"github.com/mathiasbq/supervisor/internal/session"
)

type specArgs struct {
	ProjectRoot  string `json:"project_root"`
	Requirements string `json:"requirements"`
	OutputPath   string `json:"output_path"`
	Context      string `json:"context"`
	Model        string `json:"model"`
	SessionID    string `json:"session_id"`
}

// Handle dispatches the MCP tool call to the appropriate handler.
func (s *Skill) Handle(ctx context.Context, tool string, args json.RawMessage) (json.RawMessage, error) {
	if tool != "spec" {
		return nil, fmt.Errorf("unknown tool: %s", tool)
	}
	var a specArgs
	if err := json.Unmarshal(args, &a); err != nil {
		return nil, fmt.Errorf("parse args: %w", err)
	}
	if a.ProjectRoot == "" {
		return nil, fmt.Errorf("project_root is required")
	}
	if a.Requirements == "" {
		return nil, fmt.Errorf("requirements is required")
	}
	outputPath := a.OutputPath
	if outputPath == "" {
		outputPath = "docs/spec.md"
	}

	model := a.Model
	if model == "" {
		model = s.cfg.DefaultModel
	}

	brainCtx, _ := brain.Query(ctx, s.cfg.IngestBaseURL, a.Requirements+" "+a.Context, 3)

	task := fmt.Sprintf(
		"phase: spec\nproject_root: %s\nrequirements: %s\noutput_path: %s\ncontext: %s\nmodel: %s",
		a.ProjectRoot, a.Requirements, outputPath, a.Context, model,
	)
	task = session.PrependHistory(s.cfg.SessionsDir, a.SessionID, "spec", task)
	if brainCtx != "" {
		task = brainCtx + "\n---\n\n" + task
	}

	if s.cfg.CompleteFunc == nil {
		return nil, fmt.Errorf("no executor configured")
	}
	t0 := time.Now()
	text, dur, err := s.cfg.CompleteFunc(ctx, model, s.cfg.SkillPrompt, task)
	if err != nil {
		return nil, err
	}

	if a.SessionID != "" && s.cfg.SessionsDir != "" {
		msg := text
		if len(msg) > 200 {
			msg = msg[:200]
		}
		_ = session.Append(s.cfg.SessionsDir, a.SessionID, session.Entry{
			SessionID:   a.SessionID,
			Timestamp:   time.Now(),
			Skill:       "spec",
			Phase:       "spec",
			ProjectRoot: a.ProjectRoot,
			FinalStatus: "ok",
			ModelUsed:   model,
			DurationMs:  time.Since(t0).Milliseconds(),
			Message:     msg,
		})
	}

	return json.Marshal(map[string]any{"text": text, "model": model, "duration_ms": dur})
}