// Package harness talks to the harness runner (design 5.2): proposals, approval, execution, catalogue, scenarios.
package harness

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"
)

type Client struct {
	BaseURL string // http://10.20.0.11:8080
	HTTP    *http.Client
}

func New(base string) *Client {
	return &Client{BaseURL: strings.TrimRight(base, "/"), HTTP: &http.Client{Timeout: 11 * time.Minute}}
}

func (c *Client) call(ctx context.Context, method, path string, body any, out any) (int, error) {
	var rd io.Reader
	if body != nil {
		b, _ := json.Marshal(body)
		rd = bytes.NewReader(b)
	}
	req, err := http.NewRequestWithContext(ctx, method, c.BaseURL+path, rd)
	if err != nil {
		return 0, err
	}
	if body != nil {
		req.Header.Set("Content-Type", "application/json")
	}
	resp, err := c.HTTP.Do(req)
	if err != nil {
		return 0, err
	}
	defer resp.Body.Close()
	rb, _ := io.ReadAll(io.LimitReader(resp.Body, 4<<20))
	if out != nil && len(rb) > 0 {
		if err := json.Unmarshal(rb, out); err != nil {
			return resp.StatusCode, fmt.Errorf("harness %s %s: status %d, body not JSON: %s", method, path, resp.StatusCode, truncate(string(rb), 300))
		}
	}
	if resp.StatusCode/100 != 2 {
		return resp.StatusCode, fmt.Errorf("harness %s %s: status %d: %s", method, path, resp.StatusCode, truncate(string(rb), 300))
	}
	return resp.StatusCode, nil
}

type Proposal struct {
	Token     string  `json:"token"`
	ExpiresIn float64 `json:"expires_in_s"`
	Approved  bool    `json:"approved"`
}

// Propose registers a layer-2 proposal (POST /proposals); the harness records the proposal event and returns the token.
func (c *Client) Propose(ctx context.Context, runID, scenarioID *string, actionID string, target, diagnosis map[string]any, ttl time.Duration) (*Proposal, error) {
	body := map[string]any{"run_id": runID, "scenario_id": scenarioID, "action_id": actionID, "target": target, "diagnosis": diagnosis}
	if ttl > 0 {
		body["ttl_seconds"] = int(ttl.Seconds())
	}
	var p Proposal
	if _, err := c.call(ctx, "POST", "/proposals", body, &p); err != nil {
		return nil, err
	}
	return &p, nil
}

// Approve marks the proposal approved (POST /proposals/{token}/approve); the harness records the approval event.
func (c *Client) Approve(ctx context.Context, token, by string) error {
	_, err := c.call(ctx, "POST", "/proposals/"+token+"/approve", map[string]any{"approved_by": by}, nil)
	return err
}

// Reject records the rejection (POST /proposals/{token}/reject).
func (c *Client) Reject(ctx context.Context, token, by, reason string) error {
	_, err := c.call(ctx, "POST", "/proposals/"+token+"/reject", map[string]any{"rejected_by": by, "reason": reason}, nil)
	return err
}

// Execute runs the catalogue action with the approved token (POST /actions/execute). The body is returned as-is for the
// Discord message; a non-2xx status is an error with the body text.
func (c *Client) Execute(ctx context.Context, token, actionID string, target map[string]any, runID, scenarioID *string, note string) (map[string]any, error) {
	body := map[string]any{"action_id": actionID, "target": target, "token": token, "run_id": runID, "scenario_id": scenarioID, "note": note}
	var out map[string]any
	_, err := c.call(ctx, "POST", "/actions/execute", body, &out)
	return out, err
}

type CatalogEntry struct {
	ActionID string `json:"action_id"`
	Layer    string `json:"layer"`
	Exec     bool   `json:"harness_executes"`
}

func (c *Client) Catalog(ctx context.Context) ([]CatalogEntry, error) {
	var out []CatalogEntry
	_, err := c.call(ctx, "GET", "/actions/catalog", nil, &out)
	return out, err
}

type Scenario struct {
	ID    string `json:"scenario_id"`
	Label string `json:"ground_truth_label"`
}

func (c *Client) Scenarios(ctx context.Context) ([]Scenario, error) {
	var out []Scenario
	_, err := c.call(ctx, "GET", "/scenarios", nil, &out)
	return out, err
}

func truncate(s string, n int) string {
	if len(s) <= n {
		return s
	}
	return s[:n] + "..."
}