// Copyright (C) 2023 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import m from 'mithril';
import type {duration, TimeSpan} from '../../base/time';
import type {Trace} from '../../public/trace';
import type {Engine} from '../../trace_processor/engine';
import {
  LONG,
  NUM_NULL,
  STR,
  STR_NULL,
} from '../../trace_processor/query_result';
import {TreeNode} from '../../widgets/tree';
import {DurationWidget} from '../widgets/duration';
import type {Utid} from '../sql_utils/core_types';

// An individual node of the thread state breakdown tree.
class Node {
  parent?: Node;
  children: Map<string, Node>;
  dur: duration;
  startsCollapsed: boolean = true;

  constructor(parent?: Node) {
    this.parent = parent;
    this.children = new Map();
    this.dur = 0n;
  }

  getOrCreateChild(name: string) {
    let child = this.children.get(name);
    if (!child) {
      child = new Node(this);
      this.children.set(name, child);
    }
    return child;
  }

  addDuration(dur: duration) {
    let node: Node | undefined = this;
    while (node !== undefined) {
      node.dur += dur;
      node = node.parent;
    }
  }
}

// Thread state breakdown data (tree).
// Can be passed to ThreadStateBreakdownTreeNode to be rendered as a part of a
// tree.
export interface BreakdownByThreadState {
  root: Node;
}

// Compute a breakdown of thread states for a given thread for a given time
// interval.
export async function breakDownIntervalByThreadState(
  engine: Engine,
  range: TimeSpan,
  utid: Utid,
): Promise<BreakdownByThreadState> {
  // TODO(altimin): this probably should share some code with pivot tables when
  // we actually get some pivot tables we like.
  const query = await engine.query(`
    INCLUDE PERFETTO MODULE sched.time_in_state;
    INCLUDE PERFETTO MODULE sched.states;
    INCLUDE PERFETTO MODULE android.cpu.cluster_type;

    SELECT
      sched_state_io_to_human_readable_string(state, io_wait) as state,
      state AS rawState,
      cluster_type AS clusterType,
      cpu,
      blocked_function AS blockedFunction,
      dur
    FROM sched_time_in_state_and_cpu_for_thread_in_interval(${range.start}, ${range.duration}, ${utid})
    LEFT JOIN android_cpu_cluster_mapping USING(cpu);
  `);
  const it = query.iter({
    state: STR,
    rawState: STR,
    clusterType: STR_NULL,
    cpu: NUM_NULL,
    blockedFunction: STR_NULL,
    dur: LONG,
  });
  const root = new Node();
  for (; it.valid(); it.next()) {
    let currentNode = root;
    currentNode = currentNode.getOrCreateChild(it.state);
    // If the CPU time is not null, add it to the breakdown.
    if (it.clusterType !== null) {
      currentNode = currentNode.getOrCreateChild(it.clusterType);
    }
    if (it.cpu !== null) {
      currentNode = currentNode.getOrCreateChild(`CPU ${it.cpu}`);
    }
    if (it.blockedFunction !== null) {
      currentNode = currentNode.getOrCreateChild(`${it.blockedFunction}`);
    }
    currentNode.addDuration(it.dur);
  }
  return {
    root,
  };
}

function renderChildren(
  trace: Trace,
  node: Node,
  totalDur: duration,
): m.Child[] {
  const res = Array.from(node.children.entries()).map(([name, child]) =>
    renderNode(trace, child, name, totalDur),
  );
  return res;
}

function renderNode(
  trace: Trace,
  node: Node,
  name: string,
  totalDur: duration,
): m.Child {
  const durPercent = (100 * Number(node.dur)) / Number(totalDur);
  return m(
    TreeNode,
    {
      left: name,
      right: [
        m(DurationWidget, {trace, dur: node.dur}),
        ` (${durPercent.toFixed(2)}%)`,
      ],
      startsCollapsed: node.startsCollapsed,
    },
    renderChildren(trace, node, totalDur),
  );
}

interface BreakdownByThreadStateTreeNodeAttrs {
  trace: Trace;
  dur: duration;
  data: BreakdownByThreadState;
}

// A tree node that displays a nested breakdown a time interval by thread state.
export class BreakdownByThreadStateTreeNode
  implements m.ClassComponent<BreakdownByThreadStateTreeNodeAttrs>
{
  view({attrs}: m.Vnode<BreakdownByThreadStateTreeNodeAttrs>): m.Child[] {
    return renderChildren(attrs.trace, attrs.data.root, attrs.dur);
  }
}
