package tools

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

	"git.d-ma.be/mathias/gitea-mcp/internal/allowlist"
	"git.d-ma.be/mathias/gitea-mcp/internal/gitea"
	"git.d-ma.be/mathias/gitea-mcp/internal/registry"
)

type IssueLabel struct {
	c *gitea.Client
	a *allowlist.Allowlist
}

func NewIssueLabel(c *gitea.Client, a *allowlist.Allowlist) *IssueLabel {
	return &IssueLabel{c: c, a: a}
}

func (t *IssueLabel) Descriptor() registry.ToolDescriptor {
	return registry.ToolDescriptor{
		Name:        "issue_label",
		Description: "Add labels to an issue or pull request. Resolves label names to IDs via the repo's label list. Additive — existing labels are left in place.",
		InputSchema: json.RawMessage(`{
			"type":"object",
			"properties":{
				"owner":{"type":"string"},
				"repo":{"type":"string"},
				"number":{"type":"integer","minimum":1},
				"labels":{"type":"array","items":{"type":"string"},"description":"Label names to resolve and apply. Either labels or label_ids is required."},
				"label_ids":{"type":"array","items":{"type":"integer"},"description":"Label IDs to apply directly, skipping name resolution. Either labels or label_ids is required."}
			},
			"required":["owner","repo","number"]
		}`),
	}
}

type issueLabelArgs struct {
	Owner    string   `json:"owner"`
	Repo     string   `json:"repo"`
	Number   int      `json:"number"`
	Labels   []string `json:"labels,omitempty"`
	LabelIDs []int64  `json:"label_ids,omitempty"`
}

func (t *IssueLabel) Call(ctx context.Context, raw json.RawMessage) (json.RawMessage, error) {
	var args issueLabelArgs
	if err := parseArgs(raw, &args); err != nil {
		return nil, err
	}
	if err := t.a.Check(args.Owner); err != nil {
		return nil, err
	}
	if args.Number < 1 {
		return nil, fmt.Errorf("number must be >= 1: %w", gitea.ErrValidation)
	}
	if len(args.Labels) == 0 && len(args.LabelIDs) == 0 {
		return nil, fmt.Errorf("labels is required: %w", gitea.ErrValidation)
	}

	ids := append([]int64{}, args.LabelIDs...)
	if len(args.Labels) > 0 {
		existing, err := t.c.ListLabels(ctx, args.Owner, args.Repo)
		if err != nil {
			return nil, err
		}
		byName := make(map[string]int64, len(existing))
		for _, l := range existing {
			byName[l.Name] = l.ID
		}
		for _, name := range args.Labels {
			id, ok := byName[name]
			if !ok {
				return nil, fmt.Errorf("label %q not found in %s/%s: %w", name, args.Owner, args.Repo, gitea.ErrValidation)
			}
			ids = append(ids, id)
		}
	}

	labels, err := t.c.AddIssueLabels(ctx, args.Owner, args.Repo, args.Number, ids)
	if err != nil {
		return nil, err
	}
	return textOK(labels)
}