package ai

import (
	"fmt"
	"strings"
	"time"

	"gitea.oblak.solutions/dimitar/gitFlow/pkg/status"
)

// BuildPrompt renders a scan result as an LLM instruction: a repository
// status table plus strict output rules for the suggestion schema.
func BuildPrompt(result status.ScanResult) string {
	var b strings.Builder
	fmt.Fprintf(&b, "You are gitflow, a Git repository health assistant. "+
		"A scan of %q at %s found %d repositories.\n\n",
		result.ParentDir, result.ScannedAt.Format(time.RFC3339), len(result.Repos))

	b.WriteString("Repository status table:\n")
	b.WriteString("| name | status | branch | ahead | behind | changes |\n")
	b.WriteString("|---|---|---|---|---|---|\n")
	for _, r := range result.Repos {
		fmt.Fprintf(&b, "| %s | %s | %s | %d | %d | %s |\n",
			r.Name, r.Status, branchLabel(r), r.AheadBy, r.BehindBy, changeSummary(r))
	}

	attention := result.NeedsAttention()
	fmt.Fprintf(&b, "\n%d of %d repositories need attention.\n\n", len(attention), len(result.Repos))

	b.WriteString(`Return ONLY a JSON array of suggestions. Each suggestion has exactly these fields:
- "repo_path": absolute path of the repository
- "action": one of "commit", "push", "pull", "stash", "create_pr", "cleanup", "inspect"
- "message": one short sentence explaining the next step
- "command": a concrete git command to run, or "" if none is safe
- "priority": 0 (low), 1 (medium), or 2 (high)

Rules:
- Only suggest actions for repositories that need attention.
- Prefer the smallest safe step; never suggest destructive commands.
- Do not invent repositories that are not in the table.
- If nothing needs attention, return [].
`)
	return b.String()
}

func branchLabel(r status.RepoInfo) string {
	if r.Branch == "" {
		return "(none)"
	}
	return r.Branch
}

// changeSummary renders staged/modified/untracked counts for the prompt.
func changeSummary(r status.RepoInfo) string {
	parts := make([]string, 0, 3)
	if n := len(r.StagedFiles); n > 0 {
		parts = append(parts, fmt.Sprintf("%d staged", n))
	}
	if n := len(r.ModifiedFiles); n > 0 {
		parts = append(parts, fmt.Sprintf("%d modified", n))
	}
	if n := len(r.UntrackedFiles); n > 0 {
		parts = append(parts, fmt.Sprintf("%d untracked", n))
	}
	if len(parts) == 0 {
		return "none"
	}
	return strings.Join(parts, ", ")
}